Insulin has diverse effects on metabolism. It promotes glycogen synthesis, protein synthesis and lipogenesis. In most instances, insulin action leads to a more dephospho form of the key metabolic enzymes. In this proposal, we intend to study the effects of insulin on phosphoprotein phosphatase(s), acting on protein kinase, glycogen synthase, phosphorylase kinase and histone. Activation of phosphatase(s) will result in less active protein kinase and an incrase in glycogen synthase. The objectives of this proposal are to obtain information about how insulin acts on phosphoprotein phosphatase(s) in some types of diabetes. Diaphragms and fat cells of normal fed, fasted streptozotocin diabetic and prednisone treated rats will be used as tissue sources. The phosphoprotein phosphatase(s) activity will be studied in these tissues before and after insulin treatment.